1. Field of the Invention
The invention relates to substitutes for common table salt in food and beverages. More specifically, the present invention relates to compositions containing bitterness inhibitors that reduce the bitter taste, and increase the salty taste, of potassium chloride used in foods or beverages as a substitute for sodium chloride. The compositions contain as bitterness inhibitors mixtures of taurine or a physiologically acceptable salt thereof, with 5′-nucleotide monophosphates or physiologically acceptable salts thereof. Furthermore, the present invention relates to methods of using these compositions and methods for preparing them.
2. Background Art
The sensation of taste has a profound biological significance with ramifications beyond providing people with pleasurable culinary experiences. Taste conveys many cues to humans and other animals. For example, the ability to taste allows us to identify tainted or spoiled foods, and provides satisfying responses that may be proportionate to caloric or nutritive value.
There are generally considered to be five categories of taste: sweet, sour, bitter, salty and umami (savory) (McGregor, R., Food Technol. 58(5):24-30 (2004)). These can be sub-classified as the appetitive tastes salty, sweet and umami, and the aversive tastes bitter and sour. The appetitive tastes are pleasurable and are associated with nutrient-containing foods. The aversive tastes may be elicited by toxic compounds, and thereby protect an animal by discouraging the ingestion of unhealthy or dangerous foods. Each of these tastes results from substances that may be referred to as “tastants.”
A well known salty tastant is sodium chloride (i.e., common table salt, NaCl). Sodium chloride is found in many different types of foods, condiments and beverages. Sodium chloride is also added to foods, condiments and beverages to make them more enjoyable. Unfortunately, excessive intake of sodium can increase the risk of high blood pressure and heart disease. Despite recommendations from the National Institutes of Health that persons should consume no more than 2400 mg of sodium per day, surveys show that Americans greatly exceed this amount. In fact, Americans consume more than double the recommended amount per day. This fact has prompted efforts to develop salt substitutes that contain a reduced amount of sodium.
One approach is to substitute potassium chloride as a saltening agent either partially, or wholly, for sodium chloride (Kuramitsu, R. Advances in Exp. Med. Biol., 542:227-238 (2004)). There are potassium chloride products on the market, such as Cardia Salt®, No Salt®, Morton Salt Substitute® (U.S. Pat. No. 3,505,082), and AlsoSalt® (U.S. Pat. No. 5,897,908). Many of these products include agents, such as L-lysine, to modify or mask the unpleasant taste of potassium chloride.
Recent nutritional guidelines not only suggest that the amount of sodium in the diet (ingested principally as sodium chloride) should be reduced, but that the amount of potassium in the diet should be increased. (Colorado State University Cooperative Extension-Nutrition Resources: Fact Sheet No. 9.355 “Potassium and Health” by J. Anderson, et al. (accessed May 15, 2005)). Potassium is involved in nerve function, muscle control and blood pressure. An insufficient potassium level in the body may, for example, cause muscle cramping during exercise, or cardiovascular irregularities. Id.
Consequently, substituting dietary potassium chloride for sodium chloride could provide at least two health benefits. First, it would reduce sodium intake, which could decrease risk of hypertension and associated heart disease. Second, it would increase potassium intake, which is below recommended levels in most modern diets. Despite these benefits, substituting potassium chloride for sodium chloride faces a major obstacle because potassium has a strong bitter taste.
Another obstacle to the development of a palatable potassium chloride salt substitute is the requirement that flavorings added to food or beverages meet Flavor and Extract Manufacturers Association, Generally Recognized as Safe (FEMA GRAS) guidelines or be approved by the U.S. Food and Drug Administration. Substances that might be used to inhibit the bitter taste of potassium must meet these guidelines. The use of bitterness inhibitors not already accepted by FEMA GRAS present increased development costs and delayed market entry for food and beverage companies trying to develop better salt substitutes.
Attempts to eliminate the bitter taste of potassium chloride have taken two distinct approaches. One is to use “maskers” to cover the bitter taste. These maskers are highly flavorful ingredients such as onion, garlic, paprika, red pepper, chili powder, and other spices. None of these mixtures have found wide-spread acceptance, probably because the bitter taste of potassium is still detectable. The second approach is to use compounds that reduce the bitter taste of potassium without imparting another unpleasant taste. U.S. Pat. No. 5,631,299, Kurtz et al., discloses that taurine may reduce the bitter taste of potassium chloride without producing another unpleasant taste, if used in the right amount. (See U.S. Pat. No. 5,631,299, which is incorporated by reference in its entirety).
Methods for identifying compounds that reduce bitter taste (e.g., the inhibition of activation of taste receptors) have been described by Margolskee et al. in U.S. Pat. No. 6,540,978, which is incorporated by reference in its entirety. Such methods have resulted in the identification of compounds such as 5′-adenosinic acid (AMP) and 5′-inosinic acid (IMP) as potential “bitterness inhibitors.”
Other examples of compounds proposed for use in a salt substitute to reduce or mask the bitter taste of potassium chloride include fumaric acid (U.S. Pat. No. 3,505,082), lactose and/or dextrose and cream of tartar (U.S. Pat. No. 3,860,732), potassium phosphate (U.S. Pat. No. 4,243,691) autolyzed yeast (U.S. Pat. No. 4,297,375), lysine monohydrochloride (U.S. Pat. No. 5,897,908), and specific combinations of sulfate-containing and chloride containing salts (U.S. Pat. No. 6,541,050).
Existing approaches for blocking the bitterness of potassium in salt substitutes have been unsuccessful because they do not reduce bitterness to a level satisfactory to consumers. Therefore, the undesirable bitter taste of potassium chloride remains a problem. In fact, some major food and beverage companies have objected to regulations that would lower the maximum amount of sodium allowed in foods labeled healthy, because consumers would not find these foods palatable, and viable substitutes for sodium chloride are unavailable. (See comments by ConAgra Foods to the FDA on Nov. 30, 2004 and by Quaker Foods & Beverages to the FDA on Jul. 10, 2003 regarding the FDA proposed regulations for a more restrictive sodium level).